No Slam Dunks

There are no easy answers to diagnosing copper deficiencies in your cow herd.

Becky Mills | Mar 01, 2004

If you're a producer who insists on quick, concise answers to production problems, a copper deficiency, especially a borderline case, will send you over the edge. Both the diagnosis and the corrections are littered with vague words and phrases like maybe, might, possibly, could and it depends.

In J.L. Paulk's commercial herd, the first symptom of a copper deficiency wasn't the usual visible one — black cows showing a tinge of red in their coats. His black cows were and are still black.

But last June, the Ambrose, GA, producer noticed 12 cows cycling that he thought were pregnant. For most producers, 12 open cows out of 300 would be celebrated, but Paulk normally only culls one or two annually for breeding failure.

“It was happening in different herds with different bulls,” he reports.

In August, the signs became more obvious. Eight cows due to calve in October and November aborted late-term fetuses or had premature calves.

And it wasn't a lack of groceries. Paulk tries to keep his cows in a body condition score (BCS) 6 year-round (with BCS 1 being emaciated and 10 being obese).

In the summer, the cattle graze well-managed bermuda and bahia pastures, and rye in the winter. They also get good-quality hay, whole cottonseed and ground feed as needed, especially during breeding season.

He had his forages tested for nitrates. They were within acceptable levels. He tested his well and pond water for chemical contamination. Negative.

However, University of Florida researcher John Arthington prefers cow liver biopsies for a definitive diagnosis.

“It has to be an extreme case before blood samples can be an accurate indicator of copper deficiency,” he explains. “If animals are stressed, and that stress can be a trip through the chute, they manufacture a stress protein in the blood that contains copper.”

Why Low Copper?

Paulk's next question was why copper levels in his cows and aborted fetuses were low. He keeps free-choice mineral in front of cows all year. But when Pence checked the tags on the mineral bags, he found they were under the recommended level for copper. He contacted the mineral company and copper levels were adjusted.

According to Pence, this is a common challenge. “In a lot of areas, we tend to lose our beef industry infrastructure. Mineral and feed companies tend to carry a multi-species mineral as a kind of safety net,” he says.

He says the same levels of copper usually needed for cattle are toxic to sheep.

“In Georgia, unless there's a warning on the mineral label that it's toxic to sheep, it probably doesn't have a high enough copper level for cattle,” he says.

As for a blanket recommendation, forget it. “Ask your local county agent or Extension person,” Pence advises. “It varies from area to area.” In Georgia, however, he recommends 2,500 parts per million (ppm) of copper in a mineral mix for cattle.

In other areas, that figure could be higher or lower. Besides the fact that different soils and water contain varying levels of copper, other elements factor in, too. Iron, sulfur and molybdenum all interfere with copper uptake, causing what nutritionists refer to as a secondary deficiency. A primary deficiency is when cows just plain aren't getting enough copper in their diets.

Pence notes that fungus-infected fescue can interfere with the cow's absorption of copper, but Paulk doesn't have fescue in his pastures.

After more detective work, he found copper had been dropped from his fertilizer distributor's base mix. He's going back to a complete fertilizer mix containing trace elements.

Another possible contributing factor could be the ammonium sulfate he was using as a fertilizer. Sulfur is among the elements that can be antagonistic to copper and cut its availability to forages and cattle.

Arthington stresses, “Ammonium sulfate can contribute a substantial amount of sulfur to forages but that doesn't mean it will cause copper antagonisms. In some environments, the sulfur accumulates. Still, our recommendation is to choose a fertilizer source on a per-unit cost of nitrogen basis, regardless of the sulfur content.”

He says a producer can protect himself by having forages tested. “If the sulfur levels are above 0.20%, there's probably no benefit to the forages, and the amount of sulfur might be harmful to the cattle. If they're below 0.20%, there is no harm and forage yield might actually improve with the addition of sulfur through ammonium sulfate fertilizer,” he says.

Should you start checking for a copper deficiency in your herd? It depends.

In Georgia, the answer is likely yes. In 2000, Pence drew blood from around 660 calves from different producers' herds across the state. The calves were headed for Iowa feedlots as part of Georgia's retained-ownership program and had been vaccinated and preconditioned at least 30-60 days after weaning. Almost half had marginal copper levels.

He also looked at mineral tags from around 25% of those herds. “They listed a lower level of copper supplementation than is required,” he reports.

Once again, though, there were no visible signs in the calves.

“In animals deficient in copper, we think one of the first systems affected is the immune system,” Pence says. “It doesn't shut off, it just doesn't function at an optimum level. The animals aren't really sick or dying, they aren't just growing or producing like they should.”

Larry Thompson, another UG veterinarian says there's a condition he calls “copper responsive.” “Nobody can slam their fist on the table and say these animals are deficient, but they do better when you supplement them with copper,” he says.

Montana is another state where copper is short.

“Much of the grass hay and native range is below the NRC requirements for copper,” says Montana State University Extension beef specialist John Paterson. NRC's requirement for total dietary copper is 10 ppm, but Montana forages tend to fall in the 5- to 7-ppm range.

He adds, “We also have secondary deficiencies because of too much sulfur in the water and molybdenum in the forages.”

“The blood levels were routinely low, except in herds where people have done an aggressive job of mineral supplementation to correct the situation,” he reports.

Copper deficiency can also be a problem in areas where molasses or corn gluten supplements are used.

“Molasses is naturally high in sulfur, which can act as an antagonist to copper,” Arthington says. “It can contain 0.7% to 1% sulfur.” Though, he adds, cattle normally don't eat enough molasses supplement for it to be a problem.

But, corn gluten feed is very high in sulfur. Since it's dry, producers tend to feed more of it, he says.

If you suspect a copper deficiency in your herd, Pence says to first check the label on the mineral bag. Checking the tags from one manufacturer, he found copper levels ranging from 10 ppm to 2,500 ppm.

There's also confusion in mineral mixes — some companies list the elements in ppm, others as a percent, which makes it hard to compare them, says Louise Paulk, J.L.'s wife.

Then, take forage and soil samples. “If the soil has an adequate level of copper and the blood level is deficient, there's something wrong in the loop because the cow isn't absorbing the copper,” Pence adds.

The Paulks give recordkeeping partial credit for finding the deficiency. “Evaluate the history of the cow,” says Louise. “That's how J.L. figured out something was wrong.”

“If she is five years old and has always bred on time, you need to figure out why she didn't breed before you cull her,” Paulk states.

“Get somebody to sleeve her that knows what they're feeling and get a blood test,” he says. “Ask yourself if something has changed.”

It would be nice to say the Paulks' problems were solved by adjusting the mineral mix, but they don't know. They won't know until next calving season. “Time will tell,” he says.

Pence doesn't consider it an open and shut case, either. “I'm reluctant to say copper deficiency caused their problem. But the problem did subside with copper supplementation. Copper may have been a contributing factor in this case,” he says.

Becky Mills is a freelance agricultural writer in Cuthbert, GA.

More Questions

If a producer calls Montana Extension beef specialist John Paterson about a possible copper deficiency in his herd, Paterson answers with more questions.

Paterson asks, “Have you seen a decrease in reproduction? If you have black cattle, have they acquired a red tinge to their hair coat? Have you seen issues with foot rot, especially with replacement heifers that might be in a dry lot situation?”

While foot rot is generally associated with zinc deficiency, Paterson says, “No one element is a silver bullet. What we're forced to do is provide a nutritional balance.”

Coincidence or not, Georgia producer J.L. Paulk says he had foot rot in his herd a year before his cows had reproduction problems.

Paterson continues, “Have you seen unexplained respiratory sickness in calves, even though they've been vaccinated?”

If Paterson gets a yes on one or more of his questions, he asks more. “Are protein and energy adequate? Those are answered with a body condition score. The cows may not be getting enough to eat,” he says.

University of Florida researcher John Arthington comments, “Copper deficiency gets blamed for a lot of problems it doesn't cause. There are only a few incidences where copper deficiencies cause production problems. Over-supplementation of copper may actually induce deficiencies in other essential trace minerals like zinc.”

Paterson adds, “If the cattle have enough protein and energy and things are still in tough shape, then look at the minerals.”

“Copper, zinc, manganese and selenium are the big ones here,” he says. But, he stresses, “I'm a big advocate of a balanced nutritional program.”

He adds, “Because we've had six years of drought, vitamin A and vitamin E are also important.”